It is known that, among phospholipids, phosphatidylserine has a physiological function in the brain. As a method for producing phosphatidylserine, a method for obtaining phosphatidylserine by allowing phospholipase D to act on phosphatidylcholine is known (Patent Literature 1 and Patent Literature 2).
On the other hand, a lysophospholipid that is a kind of phospholipid means a phospholipid in which one fatty acid is connected to a glycerin backbone, and it is thought that a lysophospholipid has higher absorption into the body because its molecular weight is smaller than that of a usual phospholipid. Therefore, a lysophosphatidylserine having both structures of a lysophospholipid and phosphatidylserine can be expected to be easily absorbed into the body and have excellent physiologically activity.
Among lysophospholipids, a 2-acyl-lysophospholipid does not have a fatty acid at an sn-1 position and has a fatty acid only at an sn-2 position of the glycerin backbone. It is known that a 2-acyl-lysophospholipid is superior to a 1-acyl-lysophospholipid having a fatty acid only at an sn-1 position thereof in terms of interfacial tension, surface tension, and emulsion stability (for example, Patent Literature 3).
A 2-acyl-lysophospholipid can be obtained by hydrolyzing an ester bond at an sn-1 position of a phospholipid to isolate a fatty acid. Phospholipase A1 is known as an enzyme for hydrolyzing an ester bond at an sn-1 position; Patent Literature 4 discloses a method for converting a phospholipid into a 2-acyl-lysophospholipid by using phospholipase A1 extracted from ovaries of fishes; and Patent Literature 5 discloses the method by using phospholipase A1 produced by microorganisms.